1. Field of the Invention
The present invention relates to a sheet bundle binding apparatus which performs a binding process after collating and stacking, on a processing tray, sheets fed from an image forming apparatus or the like and stores the sheets on a stack tray, and relates to improvement of a binding processing mechanism capable of performing a binding process on a sheet bundle set from the outside.
2. Description of Related Arts
In general, there has been widely known a post-processing apparatus (finisher) which performs a binding process on sheets with images formed thereon by an image forming apparatus after collating and stacking the sheets on a processing tray. For performing a binding process, there have been known a stapling unit to perform a binding process using a staple, a press binding unit to bond overlapped sheets with pressing deformation, and a unit to bond a sheet bundle as forming a cutout portion and folding a side thereof.
Japanese Patent Application Laid-open No. 2011-184153 (FIGS. 1 and 3) discloses a post-processing apparatus which is connected to a sheet discharging port of an image forming apparatus. Here, sheets fed to the sheet discharging port of the image forming apparatus are stacked into a bundle shape on a processing tray of a subsequent post-processing apparatus, and after a binding process is performed, the sheets are stored in a stack tray at the downstream side. As a binding processing apparatus, there is disclosed a mechanism to perform a binding process with a stapling unit arranged above the processing tray. Aside from the binding mechanism, there is disclosed a non-staple binding mechanism to perform pressure-bonding on a stacked sheet bundle as vertically pressure-nipping the sheet bundle with corrugation-shaped pressing faces.
As an apparatus which performs a post-process such as a binding process after collating and stacking sheets discharged from an image forming apparatus and stores the sheets on a stack tray, there have been known a stand-alone structure disclosed in Japanese Patent Application Laid-open No. 2011-184153 and an inner finisher structure that a post-processing unit is assembled into a sheet discharging area of an image forming apparatus.
With either structure, such an apparatus is used as a system in which finishing process conditions are set as a mode as well as image forming conditions, and after the setting, processes from image forming to finishing are performed as a series of job.
Japanese Patent Application Laid-open No. 2011-190021 (FIGS. 1 and 3) discloses an apparatus in which an inserter unit to insert a front sheet or the like is connected to a post-processing apparatus to store sheets fed from an image forming apparatus on a stack tray and in which a binding process is performed on image-formed sheets with a front sheet overlapped. Here, a manual setting portion to set a sheet bundle from the outside is arranged at a housing (apparatus housing) of the inserter unit and a binding process is performed on the sheet bundle manually set at the manual setting portion.
A setting face (base) on which a sheet bundle is set and a stapling unit with which a binding process is performed on the sheet bundle are incorporated in the manual setting portion. That is, there is disclosed an apparatus which can perform a process (stationery process) of binding a sheet bundle set from the outside to an external casing in addition to a bookbinding function to perform a binding process after collating and stacking sheets fed from a sheet discharging path.
Further, the above apparatus adopts a structure to perform a binding process while an external casing includes a setting portion having a slit-shape in the vertical direction and a stapling unit is incorporated in the setting portion.